“We’ve heard anecdotal evidence about these discharges, yet we don’t have the data to assess if, when, and how often this might be happening,” Bennet said.

The bill would have the GAO examine the services’ mental health assessment protocols, data on any treatment received prior to a discharge and how many troops received a discharge that prevents them from getting VA benefits.

The bill also seeks more information whether troops are counseled on the potential loss of their VA benefits before they accept a dishonorable discharge or bad-conduct discharge in lieu of a court-martial.

“This bill will help us learn if service members are losing their benefits because of behavior related to mental trauma from combat. It can serve as a basis for discussion about potential policy changes. There is no reason we shouldn’t be able to strike a balance between providing for our veterans and allowing the military to effectively enforce discipline,” Bennet said.

Lawmakers already have been pressing the Pentagon to examine 31,000 discharges since 2001 for adjustment disorders and personality disorders, mental health conditions considered to presage military service and generally not considered compensable conditions.

A defense disability review board is currently reviewing thousands of military mental health discharges for those whose diagnoses were changed to a non-compensable condition during a medical evaluation board.

The fiscal 2014 defense authorization bill also calls for the Government Accountability Office to evaluate the use of personality and adjustment disorder discharges by the services since Jan. 1, 2007.

An investigation in May by the Colorado Springs Gazette found that annual misconduct discharges have increased more than 25 percent since 2009, with an even sharper rise among combat veterans.

The review found that some troops were dismissed for offenses that could have resulted from symptoms of traumatic brain injury and PTSD.